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13482-22-9Relevant academic research and scientific papers
One-pot Synthesis of 4-Aminocyclohexanol Isomers by Combining a Keto Reductase and an Amine Transaminase
Sviatenko, Olha,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,Venkata Manideep, Kollipara,Merdivan, Simon,Günther, Sebastian,Süss, Philipp,H?hne, Matthias
, p. 5794 - 5799 (2019)
The efficient multifunctionalization by one-pot or cascade catalytic systems has developed as an important research field, but is often challenging due to incompatibilities or cross-reactivities of the catalysts leading to side product formation. Herein we report the stereoselective preparation of cis- and trans-4-aminocyclohexanol from the potentially bio-based precursor 1,4-cyclohexanedione. We identified regio- and stereoselective enzymes catalyzing reduction and transamination of the diketone, which can be performed in a one-pot sequential or cascade mode. For this, we identified regioselective keto reductases for the selective mono reduction of the diketone to give 4-hydroxycyclohexanone. The system is modular and by choosing stereocomplementary amine transaminases, both cis- and trans-4-aminocyclohexanol were synthesized with good to excellent diastereomeric ratios. Furthermore, we identified an amine transaminase that produces cis-1,4-cyclohexanediamine with diastereomeric ratios >98 : 2. These examples highlight that the high selectivity of enzymes enable short and stereoselective cascade multifunctionalizations to generate high-value building blocks from renewable starting materials. Introduction.
Histone Deacetylase Inhibitor (HDACi) Conjugated Polycaprolactone for Combination Cancer Therapy
Kularatne, Ruvanthi N.,Washington, Katherine E.,Bulumulla, Chandima,Calubaquib, Erika L.,Biewer, Michael C.,Oupicky, David,Stefan, Mihaela C.
, p. 1082 - 1089 (2018)
The short chain fatty acid, 4-phenylbutyric acid (PBA), is used for the treatment of urea cycle disorders and sickle cell disease as an endoplasmic reticulum stress inhibitor. PBA is also known as a histone deacetylase inhibitor (HDACi). We report here the effect of combination therapy on HeLa cancer cells using PBA as the HDACi together with the anticancer drug, doxorubicin (DOX). We synthesized γ-4-phenylbutyrate-?-caprolactone monomer which was polymerized to form poly(γ-4-phenylbutyrate-?-caprolactone) (PPBCL) homopolymer using NdCl3·3TEP/TIBA (TEP = triethyl phosphate, TIBA = triisobutylaluminum) catalytic system. DOX-loaded nanoparticles were prepared from the PPBCL homopolymer using poly(ethylene glycol) as a surfactant. An encapsulation efficiency as high as 88% was obtained for these nanoparticles. The DOX-loaded nanoparticles showed a cumulative release of >95% of DOX at pH 5 and 37 °C within 12 h, and PBA release was monitored by 1H NMR spectroscopy. The efficiency of the combination therapy can notably be seen in the cytotoxicity study carried out on HeLa cells, where only ～20% of cell viability was observed after treatment with the DOX-loaded nanoparticles. This drastic cytotoxic effect on HeLa cells is the result of the dual action of DOX and PBA on the DNA strands and the HDAC enzymes, respectively. Overall, this study shows the potential of combination treatment with HDACi and DOX anticancer drug as compared to the treatment with an anticancer drug alone.
Ionic liquids based on the 7-azabicyclo[2.2.1]heptane skeleton: Synthesis and properties
De Vos, Nils,Maton, Cedric,De Vreese, Peter,Brooks, Neil R.,Binnemans, Koen,Stevens, Christian V.
, p. 3741 - 3750 (2013)
Based on a previously developed method for the synthesis of epibatidine analogues, a series of new ionic liquids, based on the 7-azabicyclo[2.2.1] heptane skeleton, have been synthesized. The chemical and physical properties of the ionic liquids with bis(trifluoromethylsulfonyl)imide (Tf2N) and dicyanamide [N(CN)2] anions were investigated and they were found to exhibit very good electrochemical and thermal stabilities. Ionic liquids with the cationic part based on the structure of epibatidine (a 7-azabicyclo[2.2.1] skeleton) have been prepared. The chemical and physical properties of these ionic liquids with dicyanamide and bis(trifluoromethylsulfonyl)imide anions were investigated and they were found to show very good electrochemical and thermal stability. Copyright
High-Cluster (Cu9) Cage Silsesquioxanes: Synthesis, Structure, and Catalytic Activity
Astakhov, Grigorii S.,Bilyachenko, Alexey N.,Korlyukov, Alexander A.,Levitsky, Mikhail M.,Shul'Pina, Lidia S.,Bantreil, Xavier,Lamaty, Frédéric,Vologzhanina, Anna V.,Shubina, Elena S.,Dorovatovskii, Pavel V.,Nesterov, Dmytro S.,Pombeiro, Armando J. L.,Shul'Pin, Georgiy B.
, p. 11524 - 11529 (2018)
Unusual high-cluster (Cu9) cage phenylsilsesquioxanes were obtained via complexation of in situ CuII,Na-silsesquioxane species formed with phenanthroline and neocuproine. In the first case, phenanthroline, acting as "a silent ligand" (not participating in the composition of the final product), favors the formation of an unprecedented cagelike phenylsilsesquioxane of Cu9Na6 nuclearity, 1. In the second case, neocuproine ligands withdraws two Cu ions from the metallasilsesquioxane matrix, producing two cationic fragments Cu+(neocuproine)2. The remaining metallasilsesquioxane is rearranged into an anionic cage of Cu9Na4 nuclearity, finalizing the formation of a specific ionic complex, 2. The impressive molecular architecture of both types of complexes, e.g., the presence of different (cyclic/acyclic) types of silsesquioxane ligands, was established by single-crystal X-ray diffraction studies. Compound 1 was revealed to be highly active in the oxidative amidation of benzylic alcohol and the catalyst loading could be reduced down to 100 ppm of Cu. Catalytic studies of compound 1 demonstrated its high activity in hydroperoxidation of alkanes with H2O2 and oxidation of alcohols to ketones with tert-BuOOH.
Stereoselective conjugate addition directed by an enantiomerically pure ketal. Preparation of the cyclohexanone fragment of N-methylwelwitindolinone C isothiocyanate
Konopelski, Joseph P.,Deng, Hongbo,Schiemann, Kai,Keane, Joseph M.,Olmstead, Marilyn M.
, p. 1105 - 1107 (1998)
A cyclohexanone intermediate to be employed in the synthesis of the marine natural product N-methylwelwitindolinone C isothiocyanate has been prepared. The synthesis is diastereoselective for the production of the C12 quaternary center, which is obtained via a conjugate addition reaction directed by an adjacent chiral, nonracemic ketal. A single crystal X-ray analysis of a derivative of the final product established the absolute stereochemistry at C12.
The mechanism of the tertiary amine catalysed isomerisation of endoperoxides to hydroxyketones: Synthesis and chemistry of the intermediate postulated in the peroxide attack mechanism
Kelly, David R.,Bansal, Harjinder,Morgan
, p. 9331 - 9333 (2002)
Evidence is presented which demonstrates that the Kornblum-DeLaMare rearrangement does not proceed via nucleophilic attack of the peroxide linkage.
NMR spectroscopic conformational analysis of 4‐methylene‐ cyclohexyl pivalate—the effect of sp2 hybridization
Kleinpeter, Erich,Heydenreich, Matthias,Koch, Andreas,Krtitschka, Angela,Krüger, Tobias,Linker, Torsten
, p. 1073 - 1078 (2017)
The conformational equilibrium of the axial/equatorial conformers of 4‐methylene ‐cyclohexyl pivalate is studied by dynamic NMR spectroscopy in a methylene chloride/freon mixture. At 153 K, the ring interconversion gets slow on the nuclear magnetic resonance timescale, the conformational equilibrium (?ΔG°) can be examined, and the barrier to ring interconversion (ΔG#) can be determined. The structural influence of sp2 hybridization on both ΔG° and ΔG#of the cyclohexyl moiety can be quantified.
Liquid-Phase Catalytic Hydrogenation of 1,4-Cyclohexanedione: Activity and Selectivity
Bonnet, Marc,Geneste, Patrick,Rodrigues, Marcel
, p. 40 - 43 (1980)
Liquid-phase catalytic hydrogenation of 1,4-cyclohexanedione was carried out by using various metal catalysts on SiO2 (Ni, Cu, Pd, Pt ,Ir, Ru) in 2-propanol as solvent under low hydrogen pressure, 6.2 bar, and 20 deg C.A kinetically consecutive process, diketone -> ketol -> diol, is obtained , and 4-hydroxycyclohexanone may be obtained in a single step at a yield of 70percent by utilizing Ru/SiO2.The rate and the selectivity for the first step of the reaction giving the ketol were examined as a function of several parameters: hydrogen pressure, substrate concentration, and temperature.The kinetic orders are 1 in H2 and -0.6 in diketone with an activation energy of 11 kcal/mol.
Microreactors for oxidations using fluorine
Chambers, Richard D.,Holling, Darren,Rees, Anthony J.,Sandford, Graham
, p. 81 - 82 (2003)
Continuous flow gas-liquid thin film microreactors have been effectively used for the oxidation of alcohols and Baeyer-Villiger oxidation of ketones using elemental fluorine.
POLITAG-Pd(0) catalyzed continuous flow hydrogenation of lignin-derived phenolic compounds using sodium formate as a safe H-source
Campana, Filippo,Ferlin, Francesco,Silvetti, Matteo,Trombettoni, Valeria,Vaccaro, Luigi,Valentini, Federica
, (2021/07/09)
Phenols are aromatic biobased compounds and as they are accessible from lignin depolymerization, they can be a useful platform chemicals to produce value-added products. Herein we report our recent investigations on the definition of an approach to the efficient continuous flow selective hydrogenation of phenols in water. Our protocol is based on the use of sodium formate as a clean and safe hydrogen source in combination with our newly defined heterogeneous POLITAG-Pd(0) catalytic system. POLITAG is a polymeric heterogeneous support decorated with pincer-type ionic ligands proven to be highly efficient for the stabilization of Pd(0) nanoparticles. The results obtained are remarkable in comparison with other protocols that employ sodium formate as H-source. Indeed, our investigation has been extended to a variety of differently substituted phenolic compounds that have been hydrogenated with excellent to good selectivity in continuous flow conditions. Durability of the catalyst has been also tested with a representative continuous processing of over 100 mmol that showed no loss in efficiency and minimal metal leaching.
